Lubricants and additives for lubricating oils and greases



Patented Mar. 4, 1952 UNITED STATES PATENT OFFICE LUBRICANTS AND ADDITIVES FOR LUBRI- CATING OILS AND GREASES a corporation of Ohio No Drawingt Application February 3, 1948,

Serial No. 6,024

sclaims. 1

This invention relates to lubricants, and more particularly lubricants w'l'ii'ch are subject to severe usage conditions and in high temperature; and it is among the objects of the invention to provide lubricants having greater stability and resistance against change and having greater film strength than characteristic of usual petroleum lubricants.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indi' cative however, of but a few of the various ways in which the principle of the invention may be employed.

We have found that by reacting phosphorus pentasulfide, or other phosphorus sulfide, as phosphorus sesquisulfide, with an organic acid, products result which have efficient lubricating properties. The organic acid employed is a fatty acid, 1. e., an unsubstituted monocarboxylic acid of '12 or more carbon atoms, generally not above 22 and usually not over 18 carbon atoms. Illustrative of the acids are oleic acid, stearic acid, palmitic acid and myristic acid. Mixtures may be used and generally the saturated acids are preferred, such as mixtures having an iodine value of not over 70, and preferably less than 50, because better yields are obtained.

The reaction between the organic acid and the phosphorus sulfide is carried out at elevated temperatures, suificient for the reaction,'a'nd while reaction at low temperatures, as around 80 or 90 C. is well known to form thiophosphoric "compounds, we prefer reaction at higher temperatures, as for instance above 150 C. or whatever in each case is sufficient to break up thiophosphoric compounds, and eliminatephosphorus in a sludge or phosphorus and oxygen containing byproduct residue, and produce a product characterized by a high sulfur content in which sulfur replaces oxygen of the fatty acid. Any temperature which will .producea sludge will give a sulfur to phosphorus ratio higher than that of a thiophofsphate. In the case of the fatty acids this temperature may be as low as 250 F. Preferably a temperature of 300 F. is used and there is no need to use a temperature higher than 400 to 450 F. or temperatures which would decompose the reaction product. Usually a reaction time of onehalf to an hour or somewhat more is sufficient, depending somewhat on the temperature. The materials may be taken in calculated or molecular proportions, i. e., preferably :an amount of the sulfide theoretically equivalent to replace the oxygen in the fatty acid with sulfur from 2 the sulfide.

25% of P285 is satisfactory based on the fatty acid. A diluent may be employed during the re action.

The reaction product may be used as such, for

instance, in gearing lubrication, as in the case of a grease, or it may be incorporated-in a grease or an oil of lubricating viscosity, as for instance, oils of 40 'to 3000 viscosity Saybolt Universal at 100'F., and the amounts may befor instance0.0 5-'- 5 per cent or more such as up to 50%, since the reaction product itself is a lubricant.

With particular further advantage, the reaction product as foregoing, may be further reacted with a base, which may be an amine, ammonia or oxides or hydroxides of metals, for example aluminum, lead, tin, as illustrative of the heavier metals, and barium, calcium, potassium as illustrative of the alkali and alkaline earth metals, etc. The amines may also be used, such as diamylamine, monoamylamine, butylamine, triamylam-ine, octylamine, tributylamine, dicyclohe'xyla'mine, quinoline, dimethylamine, dipropylamine, quin'aldine, pyridine, br.ucine,1quinine, or,

other amine of aliphatic, cyclopa'raffin or heterocyclic type, of commercially suitable availability and cost. This reaction occurs readily at tem-'-- peratures in the range of 20 C. to C. These products or salts may be incorporated in the oil.

The amounts may be for instance 0.1 to 10 per cent or more.

This application is a continuation-impart, as to common subject matter, of our application Serial No. 484,238, filed April '23, 1943, now. abandoned, which in turn is a continuation inpart of our application Serial No. 297,178, filed September 29, 1939, which issued as Patent No. 2,361,957 on November '7, 1944.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or

decanted.

Generally a minimum of 20% to In order to evaluate the reaction product as an inhibitor or additive, it was added to an acid-refined S. A. E. 20 lubricating oil in an amount of 1% and tested (along with the same base oil not containing the additive) in an Ethyl Motor Operation under Procedure II, in which the operating conditions are as follows:

Type of engine, Ethyl series 30 Speed, 1200 R. P. M.

Jacket temperature, 212 F, Sump temperature, 300 F. Air-fuel ratio, 15:1 Compression ratio, 7:1 Catalyst, None The results were as follows:

Additive None Example I Amount of Additive, per cent None 1 Length of Run, hours. 20 60 Sludge 9.0 4 Acid Number 4. 2 9 Viscosity Increase 305 59 Piston Rating 8.0 3. 5 Demerit Rating 121. 2 8. 9

Example II Synethic stearic acid (hydrogenated fish oil fatty acids) was reacted with Il phosphorus pentasulfide (based on the stearic acid) at a temperature of 300 F. The reaction was continued for about 1 hour, and about 5% lime was added. An additional Il phosphoru pentasulfide was added and the reaction continued for one hour at the same temperature. An additional 5% of lime was reacted and the reaction product was separated from the by-product residue during which it was diluted with an equal amount of oil to assist in filtration. The above oil solution of the reaction product was incorporated in an amount of 6%, in an acidrefined S. A. E. 30 lubricating oil and tested and compared with a similar test on the oil not containing the additive, using an Ethyl Motor Operation by Procedure IV in which the operating conditions are as follows:

Type of engine, Ethyl series 30 Speed, 1200 R. P. M. I Jacket temperature, 212 F. Sump temperature, 300 F. Air-fuel ratio, :1 I Compression ratio, 7:1 Catalyst, 0.1% F203 as iron naphthenate The results are as follows:

amount of water.

The improvement is very marxed and is demonstrated in only 20 hours run.

Example III Lauric acid was reacted with 25% phosphorus pentasulfide for one hour at 300 F. The reaction product, after separation from the sludge. was converted into the metal derivative thereof by reaction with 10% (based on the reaction product) of lime to which was added an equal This reaction was continued at a temperature of about 180 F. for several hours and then at a temperature of about 250 F. for about one hour. The reaction product was filtered during which it was diluted with oil to form an oil solution containing 37% reaction product and 63% oil. The above oil solution of the metal derivative of the reaction product was incorporated in an acid-refined S. A. E. 30 lubricating oil in an amount of 6% and the oil containing the same was tested in an Ethyl Motor Operation by Procedure VI, and compared with a similar test on the oil not containing the ad-' ditive.

The operating conditions are as follows:

Type of engine, Ethyl series 30 Engine speed, 1200 R. P. M. Sump temperature, 300 F. Jacket temperature, 350 F. Air-fuel ratio, 12:1 Compression ratio, 7:1 Catalyst, none The results are as follows:

Additive None Example III Amount of Additive, per cent None 6 Length 01 Run, hours 20 60 40 Sludge 4. 0 1.8 Acid Numbcr 3. 25 1. 75 Viscosity Increase. 644 583 Piston Rating 6.0 3. 5 Demerit Rating... 98. 5 21. 4

This shows the improvement in cleanliness of the pistons even after a 60 hour run.

Example IV Palmitic acid was mixed with an equal proportion of a neutral lubricating oil having a viscosity of 225 S. U. S. at 100 F. and reacted with 38% phosphorus pentasulfide, based on the weight of the palmitic acid. The reaction was continued at a temperature of about 300 F. until complete, as in the previous examples, and the reaction product was separated from a sludge and then converted to the corresponding calcium derivative by reaction with 10% of lime containing an equal amount of water. The latter reaction was carried out at 300 F. under 60 pounds of pressure for about 1 hour.

The above oil solution of the metal derivative, in an amount of 4.4%, was added to the lubricating oil and tested by Procedure VI and compared with an oil not containing the additive when similarly tested. The results are as follows:

Additive None Example II Additive None Example IV Example IV Amount of Additive. per cent None 6 Amount of Additive, per cent None 4. 4 6. 6 Length of Run, hours 20 20 Length of Run, hours-.. 20 60 60 Sludge 10.0 0. 95 Sludge 4. 0 4. 0 0. 5 Acid Number 7. 25 3.0 Acid Number 3.25 2. 25 2. 0' Vi cosity. Incre 1003 89 1 1 Viscosity Increase. 644 918 638 Piston Rating 6. 5 0 Piston Rating 6.0 2.0 0.0 Demerit Rating 168. 9 24. 7 Demerit Rating 98. 5 29. 0 13.1

sta gers Example V Stearic acid is mixed with an equal amount of a; white oil (a heavily acid-treated lubricating oil)- and reacted with 35% of phosphorus penta sulfide (based on the stearic acid) at a temperature of- 250 F. until the reaction is complete, which is about 1 hour. The reaction product is separated from a sludge andconverted to the metal derivative thereof by reaction with 10% of lime containing an equal amount of water. The latter reaction is carried out at a temperature of 300 F. for about 1 hour at 100 pounds pressure. The above oil solution of the metal derivative made in accordance with this example is incorporated in a lubricating oil in an amount of 3% and tested by Procedure VI. The results are as follows:

A mixture of 25% stearic acid and 75% oleic acid is reacted with 35% phosphorus pentasulfide at a temperature of 300 F. for approximately 1 hour. The reaction product is separated from the sludge and converted to the corresponding metal derivative by reaction with 10% of lime containing an equal amount of Water. The latter reaction is carried out at 300 F. for about 1 hour under 50 pounds of pressure. The reaction product was filtered during which time an equal amount of oil was added to aid in the filtration. The above oil solution of the metal derivative so prepared is incorporated in a lubricating oil in an amount of and tested by Procedure VI. The results are as follows:

The reaction products of Examples II to VI before conversion to the metal derivative are all antioxidants of the general type of Example I, although not as detergent as the metal derivatives.

Any of the above reaction products contemplate the modifications thereof in which elemental sulfur is reacted with the reaction products.

We claim:

1. Mineral lubricating oils and greases which contain an amount to inhibit their deterioration in use of the reaction product of an unsubstituted fatty acid containing from about 12 to about 18 carbon atoms and having an iodine value of not over 70, reacted with about 20% to about 35% of a phosphorus sulfide selected from the group consisting of P2S5 and P483 at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratiohigher than that of a thiophosphate and being suitable to inhibit the reacted with about 25% phosphorus pentasulfide a'tabout-300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and: being suitable to inhibit the deterioration of lubricating oils and greases in use.

3. Mineral lubricating oils and greases which contain an amount to inhibit their deterioration in use of the reaction product of stearic acid, reacted with about 35% phosphorus pentasulfide at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

4. Mineral lubricating oils and greases which contain an amount to inhibit their deterioration in use of the reaction product of a mixture of stearic and oleic acids having an iodine value of not over 70, reacted with about 35% phosphorus pentasulfide at about 300 F. for about one hour, said reaction product containing a sulfur-tophosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

5. As a lubricant and as an addition agent for lubricating oils and greases to inhibit their dete- I rioration, the reaction product of an unsubstituted fatty acid containing from about 12 to about 18 carbon atoms and having an iodine value of not over 70, reacted with about 20 to about 35% of a phosphorus sulfide selected from the group consisting of P285 and P4S3 at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

6. As a lubricant and as an addition agent for lubricating oils and greases to inhibit their deterioration, the reaction product of lauric acid, reacted with about 25% phosphorus pentasulfide at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

7. As a lubricant and as an addition agent for lubricating oils and greases to inhibit their deterioration, the reaction product of stearic acid, reacted with about 35% phosphorus pentasulfide at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

8. As a lubricant and as an addition agent for lubricating oils and greases to inhibit their deterioration, the reaction product of a mixture of stearic and oleic acids, reacted with about 35% phosphorus pentasulfide at about 300 F. for about one hour, said reaction product containing a sulfur-to-phosphorus ratio higher than that of a thiophosphate and being suitable to inhibit the deterioration of lubricating oils and greases in use.

JOHN M. MUSSELMAN. HERMAN P. LANKELMA.

(References on following page) file of this patent:

UNITED STATES PATENTS Number};

Name Date Kaufman July 25, 1939 Lincom Sept. 5, 1939 Pru-tton May 20, 1941 Lincoln Oct. 7, 1941 Number Name v Date Zimmer Jan. 5, 1943 Kelso Apr. 6, 1943 Kelso Apr. 6, 1943 Musselman Nov. 7, 1944 Cook Dec.'26, 1944 Williams May 1, 1945 Yule May 6, 1947 Musselman July 13, 1948 

1. MINERAL LUBRICATING OILS AND GREASES WHICH CONTAIN AN AMOUNT TO INHIBIT THEIR DETERIORATION IN USE OF THE REACTION PRODUCT OF AN UNSUBSTITUTED FATTY ACID CONTAINING FROM ABOUT 12 TO ABOUT 18 CARBON ATOMS AND HAVING AN IODINE VALUE OF NOT OVER 70, REACTED WITH ABOUT 20% TO ABOUT 35% OF A PHOSPHORUS SULFIDE SELECTED FROM THE GROUP CONSISTING OF P2S5 AND P4S3 AT ABOUT 300* F. FOR ABOUT ONE HOUR, SAID REACTION PRODUCT CONTAINING A SULFUR-TO-PHOSPHORUS RATIO HIGHER THAN THAT OF A THIOPHOSPHATE AND BEING SUITABLE TO INHIBIT THE DETERIORATION OF LUBRICATING OILS AND GREASES IN USE. 